1. Field of the Invention
This invention relates to methods for the continuous production of pretzel products. In particular, the invention relates to a method of producing pretzels on a continuous basis which employs relatively low moisture. In one embodiment, the invention relates to the continuous production of a pretzel product which is subsequently continuously filled with an edible material such as a creamy or paste-like material.
2. Prior Art
The making of pretzels is an art which has been practiced for many years. Pretzels are baked products which are produced from essentially rather simple recipes containing flour, water, salt and other ingredients. Pretzels have a characteristic flavor which is imparted by chemical reactions occurring during baking and by flavoring ingredients such as malt and yeasts. They are especially characterized by the presence of a darkly browned exterior surface. It has long been known that the browned surface effect can be obtained by coating the surface of the dough mixture, prior to baking, with a caustic solution such as 0.5% aqueous NaOH. Caustic treatment not only imparts the desired browning during the baking cycle, but also contributes to the development of characteristic pretzel flavors.
In the prior art, pretzels have been produced from shaped dough mixtures containing relatively high water contents, i.e., about 40% to 50%. Since the final pretzel has a moisture content of only about 2.0%, this requires a considerably high energy input during a baking cycle in order to drive off water and achieve the desired final moisture content. The high moisture content of prior art pretzel doughs makes them relatively soft, so that, prior to baking, they tend to lose their shape easily. This is particularly true during the caustic treatment where the pretzel dough tends to become very pliable. Consequently, it has been difficult to maintain a shaped dough profile, such as a tubular or C-shaped profile suitable for injection of filling materials, using uncooked pretzel doughs of the prior art. This has made it difficult or impossible to produce filled pretzel products in a continuous process.
U.S. Pat. Nos. 4,162,333 and 4,241,649 disclose a method for producing a filled pretzel product. In accordance with this method, short tubular pieces of pretzel dough are extruded onto supporting pegs on a conveyor belt. Extrusion is conducted in a discontinuous manner as the pegs on the conveyor belt are indexed past the extruder die. The supporting pegs are required to prevent the central cavity of the pretzel dough from losing its configuration, thereby ensuring a cavity of appropriate dimensions for receiving the filling material. The individual tubular pieces are subjected to a number of further processing steps, including baking and filling. In addition to being discontinuous in nature, the process is extremely cumbersome inasmuch as it requires complex material handling equipment to handle each small tubular piece of dough without allowing it to lose its tubular configuration.
U.S. Pat. No. 3,615,675 describes a process for continuously producing a filled, puff-extruded farinaceous product. In this process, a farinaceous mixture having a moisture content of 10% to 25% is extruded through an annular die at a temperature exceeding the boiling point of the moisture in the mixture so that the farinaceus material expands due to the flash off of moisture upon emerging from the extruder. An edible, creamy or paste-like material is continuously deposited into the hollow core of the puff-extruded material by pumping the filling material through a filling tube which extends coaxially through the die orifice into the central core of the extrudate. In this process, the puffed extrudate sets up to form a dimensionally stable cylinder, susceptible of continuous processing, due to the flash off of moisture upon emerging from the die. The puffed product which is produced has texture and flavor characteristics which are different from those of pretzels.
It is an object of the present invention to provide a method for continuously producing pretzels which is energy efficient and which minimizes the amount of energy input required to dry the product to its final moisture content.
Other objects and advantages of the invention will be apparent to those skilled in the art from the following description.